Use of a process fluid with an environmentally compatible biostabilizer in a geothermal borehole

Abstract

The present invention relates to the use of a process fluid with an environmentally compatible biostabilizer in a geothermal borehole. The biostabilizer is characterized in that it comprises at least one organic acid, or a salt, alcohol or aldehyde thereof, wherein the at least one organic acid is selected from the group consisting of hop acids, resin acids, fatty acids and mixtures thereof. The biostabilizer is preferably a mixture of hop extract, rosin and myristic acid. The invention further relates to related process fluids and methods for producing the same.

The invention claimed is: 
     
       1. A method for reducing microorganisms within a geothermal borehole, comprising:
 providing water having a hardness of at most 20° dH (German hardness), adding an environmentally compatible biostabiliser to the water to form a process fluid, 
 pumping the process fluid into the geothermal borehole, wherein the environmentally compatible biostabiliser comprises at least one organic acid or alcohol thereof and the at least one organic acid is selected from the group consisting of hop acids; and the process fluid has a hardness of at most 20° dH (German hardness). 
 
     
     
       2. The method according to  claim 1 , wherein the process fluid is used as a drilling fluid in the geothermal borehole. 
     
     
       3. The method according to  claim 1 , wherein the process fluid further comprises at least one defoamer and additional additives. 
     
     
       4. The method according to  claim 3 , wherein the additional additives comprise at least one gelling agent, and wherein the gelling agent is a biopolymer or a polymeric derivative thereof. 
     
     
       5. The method according to  claim 4 , wherein the additional additives further comprise a water-softening agent. 
     
     
       6. The method according to  claim 1 , wherein the biostabiliser comprises:
 at least one resin acid, or a salt, alcohol, or aldehyde thereof, and at least one fatty acid, or a salt, alcohol, or aldehyde thereof. 
 
     
     
       7. The method according to  claim 1 , wherein the biostabiliser comprises:
 a hop acid, selected from the group consisting of humulone, isohumulone, cohumulone, adhumulone, prehumulone, posthumulone, tetrahydroisohumulone, and tetrahydrodeoxyhumulone, lupulone, colupulone, adlupulone, prelupulone, postlupulone, hexahydrocolupulone, and hexahydrolupulone; or a resin acid selected from the group consisting of pimaric acid, neoabietic acid, abietic acid, dehydroabietic acid, levopimaric acid, and palustrinic acid; or a fatty acid selected from the group consisting of capric acid, undecylenic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachinic acid, behenic acid, lignoceric acid, cerotic acid, palmitoleinic acid, oleic acid, elaidic acid, vaccenic acid, icosenoic acid, cetoleic acid, erucic acid, nervonic acid, linoleic acid, linolenic acid, arachidonic acid, timnodonic acid, clupanodonic acid, and cervonic acid. 
 
     
     
       8. The method according to  claim 1 , wherein the process fluid further comprises one or more of an additional antimicrobial agent and an additional bio stabiliser. 
     
     
       9. The method of  claim 1 , further comprising biostabilising the geothermal borehole by pumping the process fluid into the geothermal borehole. 
     
     
       10. The method according to  claim 1 , wherein the process fluid further comprises at least one gelling agent, and wherein the gelling agent is a polysaccharide of one of a starch, vegetable gum, xanthan, cellulose, polyanionic cellulose, or pectin. 
     
     
       11. The method according to  claim 1 , wherein the process fluid further comprises at least one of acetic acid, lactic acid, propionic acid, benzoic acid, sorbic acid, formic acid, and salts. 
     
     
       12. The method according to  claim 1 , wherein the hardness of the process fluid is at most 15° dH (German Hardness). 
     
     
       13. The method according to  claim 1 , wherein the hardness of the process fluid is at most 10° dH (German Hardness). 
     
     
       14. The method according to  claim 1 , wherein the hardness of the process fluid is at most 7.5° dH (German Hardness). 
     
     
       15. The method according to  claim 1 , wherein the hardness of the process fluid is at most 5° dH (German Hardness). 
     
     
       16. The method according to  claim 1 , wherein the process fluid further comprises at least one defoamer. 
     
     
       17. A process fluid for reducing microorganisms within a geothermal borehole, comprising:
 water having a hardness of at most 20° dH (German hardness), 
 an environmentally compatible biostabiliser added to the water to form the process fluid, 
 the environmentally compatible biostabiliser adapted for use in the process fluid to reduce microorganisms within the geothermal borehole, the biostabiliser comprising at least one organic acid, or alcohol thereof, wherein the at least one organic acid is selected from the group consisting of hop acids; and the process fluid has a hardness of at most 20° dH (German Hardness). 
 
     
     
       18. A process for preparing a process fluid comprising an environmentally compatible biostabilizer adapted for use in the process fluid to reduce microorganisms within a geothermal borehole, the process comprising:
 providing water having a hardness of at most 20° dH (German hardness), 
 adding an environmentally compatible biostabiliser to the water to form the process fluid, wherein the environmentally compatible biostabiliser comprises at least one organic acid or alcohol thereof, wherein the process fluid has a hardness of at most 20° dH (German Hardness), and wherein the at least one organic acid is selected from the group consisting of hop acids to obtain the process fluid.